We propose to design, implement, and test an intelligent, interactive, electronic assistant for crystallographers that will facilitate the trial-and-error process of growing crystals of biological macromolecules. The Assistant collects and analyzes laboratory data as well as historical data at the laboratory bench itself. The tasks performed by the Assistant include (a) unobtrusive recording of experimental context and maintaining an archive of crystallization experiments, (b) answering questions about experimental protocols, retrieving and analyzing experiments relevant to new crystallization attempts, (c) performing chemical calculations and simulations to assist in choice of experimental parameters, as well as (d) exploratory data analysis and the induction of causal theories that capture regularities in the sizable experimental data on crystal growth.